This invention relates to rock crusher construction, and more particularly to a lifter for remotely removing the lid from a rock crusher.
In rock crushers, particularly those of the centrifugal impact type, the operative elements of the crusher are surrounded by a cylindrical shell which in turn is covered by a removable lid in order to retain flying rock within an enclosed environment. Since crushers of this type are quite large and since the internal forces generated by the flying rock are high, the lids, along with the shell and other covering elements, are necessarily quite massive often weighing up to one ton. However, the lids must be removed frequently (anywhere from once a week to twice a day dependent on the material being crushed) in order to inspect and replace the operative elements of the crusher which are subject to rapid wear and frequent breakage due to the abrasive action of the rock material.
Accordingly, lifting equipment, such as a lift truck or front loader, must remain in waiting or else be on short notice for this purpose. In applications where the crusher is positioned well above ground level, a crane must be used for removing the lid thereby entailing large initial investment and operating costs. As a result the cost of the rock crushing operation is increased, and in many instances routine inspection for worn or broken parts is delayed or eliminated resulting in increased damage to the crusher and possible physical injury. In addition since the lid is reattached to the lifting device each time it is to be lifted, there is a likelihood of misrigging causing the raised lid to be dropped which also creates a safety hazard.